Fix members autocomplete showing non-matches

Member autocomplete using `@` incorrectly shows non-matches.
If you type `@marge.`, you are still shown the complete
list of members even though there are no matches.
This commit fixes this.

app/assets/javascripts/gfm_auto_complete.js

@@ -834,10 +834,10 @@ GfmAutoComplete.Members = {
     const lowercaseQuery = query.toLowerCase();
     const { nameOrUsernameStartsWith, nameOrUsernameIncludes } = GfmAutoComplete.Members;
 
-    return sortBy(members, [
+    return sortBy(
+      members.filter((member) => nameOrUsernameIncludes(member, lowercaseQuery)),
       (member) => (nameOrUsernameStartsWith(member, lowercaseQuery) ? -1 : 0),
-      (member) => (nameOrUsernameIncludes(member, lowercaseQuery) ? -1 : 0),
-    ]);
+    );
   },
 };
 GfmAutoComplete.Labels = {

spec/frontend/gfm_auto_complete_spec.js

@@ -691,12 +691,9 @@ describe('GfmAutoComplete', () => {
           { search: 'ErlindaMayert nicolle' },
           { search: 'PhoebeSchaden salina' },
           { search: 'KinaCummings robena' },
-          // Remaining members are grouped last
-          { search: 'Administrator root' },
-          { search: 'AntoineLedner ammie' },
         ];
 
-        it('sorts by match with start of name/username, then match with any part of name/username, and maintains sort order', () => {
+        it('filters out non-matches, then puts matches with start of name/username first', () => {
           expect(GfmAutoComplete.Members.sort(query, items)).toMatchObject(expected);
         });
       });